What is the recommended initial fluid bolus and titration rate of norepinephrine (norad) in shock?

Fluid Bolus and Norepinephrine Titration in Shock

For adults with septic shock, administer at least 30 mL/kg of crystalloid within the first 3 hours, and initiate norepinephrine as the first-choice vasopressor targeting a mean arterial pressure (MAP) of 65 mmHg, starting at 0.5-5.0 mcg/kg/min and titrating to effect. 1, 2

Initial Fluid Resuscitation

Adult Dosing

• Administer a minimum of 30 mL/kg of isotonic crystalloid within the first 3 hours for sepsis-induced hypoperfusion or elevated lactate 1, 2
• Use rapid boluses of 250-1000 mL, administered repeatedly as needed 2, 3
• Some patients may require more rapid administration and greater total volumes depending on hemodynamic response 1
• Continue fluid administration using a fluid challenge technique as long as hemodynamic parameters improve (based on dynamic measures like pulse pressure variation or static measures like arterial pressure and heart rate) 1

Pediatric Dosing

• Administer 20 mL/kg boluses of isotonic crystalloid or 5% albumin via rapid push or pressure bag 1
• Children commonly require 40-60 mL/kg in the first hour, but may need up to 200 mL/kg if no signs of fluid overload develop 1
• Administer each 20 mL/kg bolus over 15-20 minutes rather than 5-10 minutes to reduce risk of mechanical ventilation and impaired oxygenation 4
• Monitor for signs of fluid overload: increased work of breathing, rales, gallop rhythm, or hepatomegaly 1

Fluid Type Selection

• Use crystalloids (normal saline or balanced crystalloids like lactated Ringer's) as first-line therapy 1, 2, 3
• Balanced crystalloids may be preferred over normal saline to avoid hyperchloremic metabolic acidosis 2, 3
• Consider adding albumin when patients require substantial amounts of crystalloids (weak recommendation) 1, 2
• Never use hydroxyethyl starches - they are contraindicated in septic shock 1, 2

Norepinephrine Initiation and Titration

When to Start Norepinephrine

• Initiate norepinephrine early, even before completing full fluid resuscitation, if hypotension persists 5, 6
• Very early vasopressor start (within/before the next hour after first fluid bolus) is associated with reduced mortality and less total fluid administration 6
• Do not delay vasopressors waiting for arbitrary fluid volumes - profound and durable hypotension independently increases mortality 5

Norepinephrine Dosing

Adults:

• Starting dose: 0.5-5.0 mcg/kg/min via central venous access 1, 7
• Titrate to achieve MAP ≥65 mmHg 1
• Consider higher MAP targets (>65 mmHg) in patients with chronic hypertension 5
• Norepinephrine is more effective than dopamine (93% vs 31% success rate) and should be first-line 1, 7

Pediatrics:

• For warm shock (vasodilatory): titrate norepinephrine to restore normal perfusion and blood pressure 1
• For cold shock (cardiogenic): use epinephrine 0.05-0.3 mcg/kg/min instead 1
• Can start peripherally with low-dose dopamine or epinephrine while establishing central access, but reduce dose if peripheral ischemia occurs 1

Refractory Hypotension Management

• Add vasopressin 0.03 units/min when norepinephrine reaches 0.25-0.50 mcg/kg/min 1, 8
• Vasopressin addition is particularly effective when norepinephrine ≥0.30 mcg/kg/min 8
• Alternatively, add epinephrine to norepinephrine if additional agent needed 1
• Avoid vasopressin as sole initial vasopressor; doses >0.03-0.04 units/min reserved for salvage therapy 1

Factors Affecting Vasopressor Response

• Obesity and hyperlactatemia are negatively associated with vasopressin responsiveness 8
• Higher BMI, longer norepinephrine duration before vasopressin, and lower pH predict prolonged shock 8
• Rebound hypotension occurs in 9% when vasopressin terminated; risk reduced if vasopressin continued >24 hours 8

Monitoring and Reassessment

Hemodynamic Targets

• MAP ≥65 mmHg (individualize higher for chronic hypertension) 1, 5
• Capillary refill ≤2 seconds 1
• Urine output >0.5 mL/kg/hr (adults) or >1 mL/kg/hr (pediatrics) 1, 3
• Central venous oxygen saturation (ScvO2) >70% 1
• Cardiac index 3.3-6.0 L/min/m² 1
• Lactate clearance (aim for 20% reduction if elevated) 3

Assessment Technique

• Reassess after each fluid bolus for signs of improvement or fluid overload 2, 3
• Use dynamic measures (pulse pressure variation, stroke volume variation) over static measures (CVP alone) to predict fluid responsiveness 1, 2
• Place arterial catheter as soon as practical in all patients requiring vasopressors 1

Critical Pitfalls to Avoid

• Do not delay vasopressors waiting to complete arbitrary fluid volumes - early norepinephrine improves outcomes 5, 6
• Do not rely on CVP alone to guide fluid therapy - it poorly predicts fluid responsiveness 2, 9
• Do not use dopamine as first-line - norepinephrine is superior and dopamine only for highly selected patients (low arrhythmia risk, bradycardia) 1, 7
• Do not push fresh frozen plasma rapidly - infuse slowly due to vasoactive kinins and high citrate 1
• In pediatrics, do not administer boluses too rapidly - 15-20 minutes per bolus reduces ventilation requirements compared to 5-10 minutes 4
• Do not use etomidate for intubation in septic shock - associated with higher mortality 1